Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compare...Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compared to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency conversion.Here,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane metasurfaces.We demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane films.Furthermore,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave incidence.To prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane metasurfaces.Our results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.展开更多
We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing...We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing a gold mirror under a silicon nanodisk,we introduce a novel characteristic of the anapole mode through the spatial overlap of resonantly excited Cartesian electric and toroidal dipole modes.This is a remarkable improvement on the early demonstrations of the anapole mode in which the electric and toroidal modes interfere off-resonantly.Therefore,our system produces a significant near-field enhancement,facilitating the nonlinear process.Moreover,the mirror surface boosts the nonlinear emission via the free-charge oscillations within the interface,equivalent to producing a mirror image of the nonlinear source and the pump beneath the interface.We found that these improvements result in an extremely high experimentally obtained efficiency of 0.01%.展开更多
A key concept underlying the specific functionalities of metasurfaces is the use of constituent components to shape the wavefront of the light on demand.Metasurfaces are versatile,novel platforms for manipulating the ...A key concept underlying the specific functionalities of metasurfaces is the use of constituent components to shape the wavefront of the light on demand.Metasurfaces are versatile,novel platforms for manipulating the scattering,color,phase,or intensity of light.Currently,one of the typical approaches for designing a metasurface is to optimize one or two variables among a vast number of fixed parameters,such as various materials’properties and coupling effects,as well as the geometrical parameters.Ideally,this would require multidimensional space optimization through direct numerical simulations.Recently,an alternative,popular approach allows for reducing the computational cost significantly based on a deep-learning-assisted method.We utilize a deep-learning approach for obtaining high-quality factor(high-Q)resonances with desired characteristics,such as linewidth,amplitude,and spectral position.We exploit such high-Q resonances for enhancedlight–matter interaction in nonlinearoptical metasurfaces and optomechanical vibrations,simultaneously.We demonstrate that optimized metasurfaces achieve up to 400-fold enhancement of the third-harmonic generation;at the same time,they also contribute to 100-fold enhancement of the amplitude of optomechanical vibrations.This approach can be further used to realize structures with unconventional scattering responses.展开更多
In the last decades,metasurfaces have attracted much attention because of their extraordinary light-scattering properties.However,their inherently static geometry is an obstacle to many applications where dynamic tuna...In the last decades,metasurfaces have attracted much attention because of their extraordinary light-scattering properties.However,their inherently static geometry is an obstacle to many applications where dynamic tunability in their optical behaviour is required.Currently,there is a quest to enable dynamic tuning of metasurface properties,particularly with fast tuning rate,large modulation by small electrical signals,solid state and programmable across multiple pixels.Here,we demonstrate electrically tunable metasurfaces driven by thermo-optic effect and flash-heating in silicon.We show a 9-fold change in transmission by<5 V biasing voltage and the modulation rise-time of<625µs.Our device consists of a silicon hole array metasurface encapsulated by transparent conducting oxide as a localised heater.It allows for video frame rate optical switching over multiple pixels that can be electrically programmed.Some of the advantages of the proposed tuning method compared with other methods are the possibility to apply it for modulation in the visible and near-infrared region,large modulation depth,working at transmission regime,exhibiting low optical loss,low input voltage requirement,and operating with higher than video-rate switching speed.The device is furthermore compatible with modern electronic display technologies and could be ideal for personal electronic devices such as flat displays,virtual reality holography and light detection and ranging,where fast,solid-state and transparent optical switches are required.展开更多
基金the support from the Royal Society scholarshipsupport from the UK Research and Innovation Future Leaders Fellowship (MR/T040513/1).
文摘Dielectric metasurfaces play an increasingly important role in enhancing optical nonlinear generations owing to their ability to support strong light-matter interactions based on Mie-type multipolar resonances.Compared to metasurfaces composed of the periodic arrangement of nanoparticles,inverse,so-called,membrane metasurfaces offer unique possibilities for supporting multipolar resonances,while maintaining small unit cell size,large mode volume and high field enhancement for enhancing nonlinear frequency conversion.Here,we theoretically and experimentally investigate the formation of bound states in the continuum(BICs)from silicon dimer-hole membrane metasurfaces.We demonstrate that our BIC-formed resonance features a strong and tailorable electric near-field confinement inside the silicon membrane films.Furthermore,we show that by tuning the gap between the holes,one can open a leaky channel to transform these regular BICs into quasi-BICs,which can be excited directly under normal plane wave incidence.To prove the capabilities of such metasurfaces,we demonstrate the conversion of an infrared image to the visible range,based on the Third-harmonic generation(THG)process with the resonant membrane metasurfaces.Our results suggest a new paradigm for realising efficient nonlinear photonics metadevices and hold promise for extending the applications of nonlinear structuring surfaces to new types of all-optical near-infrared imaging technologies.
基金support provided by the Australian Research Council(ARC)and participation in the Erasmus Mundus NANOPHI project,contract number 20135659/002-001from an ARC Discovery Early Career Research Fellowship(DE170100250)+4 种基金supported by a UNSW Scientia Fellowshipfunding from the Australia-Germany Joint Research Cooperation Schemefrom Consejo Nacional de Ciencia y Tecnologıa(CONACYT)the financial support by NSFC(No.11774182,No.91750204)support by the German Research Foundation(STA 1426/2-1)。
文摘We demonstrate that a dielectric anapole resonator on a metallic mirror can enhance the third harmonic emission by two orders of magnitude compared to a typical anapole resonator on an insulator substrate.By employing a gold mirror under a silicon nanodisk,we introduce a novel characteristic of the anapole mode through the spatial overlap of resonantly excited Cartesian electric and toroidal dipole modes.This is a remarkable improvement on the early demonstrations of the anapole mode in which the electric and toroidal modes interfere off-resonantly.Therefore,our system produces a significant near-field enhancement,facilitating the nonlinear process.Moreover,the mirror surface boosts the nonlinear emission via the free-charge oscillations within the interface,equivalent to producing a mirror image of the nonlinear source and the pump beneath the interface.We found that these improvements result in an extremely high experimentally obtained efficiency of 0.01%.
基金supported by UNSW Scientia Fellowship and ARC Discovery Project(DP170103778)funding from ARC Discovery Early Career Research Fellowship(DE170100250)+1 种基金financial support from the Russian Foundation for Basic Research(Grants Nos.18-02-00381 and 19-02-00261)the Australian Research Council(DE19010043).
文摘A key concept underlying the specific functionalities of metasurfaces is the use of constituent components to shape the wavefront of the light on demand.Metasurfaces are versatile,novel platforms for manipulating the scattering,color,phase,or intensity of light.Currently,one of the typical approaches for designing a metasurface is to optimize one or two variables among a vast number of fixed parameters,such as various materials’properties and coupling effects,as well as the geometrical parameters.Ideally,this would require multidimensional space optimization through direct numerical simulations.Recently,an alternative,popular approach allows for reducing the computational cost significantly based on a deep-learning-assisted method.We utilize a deep-learning approach for obtaining high-quality factor(high-Q)resonances with desired characteristics,such as linewidth,amplitude,and spectral position.We exploit such high-Q resonances for enhancedlight–matter interaction in nonlinearoptical metasurfaces and optomechanical vibrations,simultaneously.We demonstrate that optimized metasurfaces achieve up to 400-fold enhancement of the third-harmonic generation;at the same time,they also contribute to 100-fold enhancement of the amplitude of optomechanical vibrations.This approach can be further used to realize structures with unconventional scattering responses.
基金The Royal Society and the Wolfson Foundation(RSWF\FT\191022)as well as the Australian Research Council through TMOS Centre of Excellence(CE20010001)and Discovery Project(DP200101353).
文摘In the last decades,metasurfaces have attracted much attention because of their extraordinary light-scattering properties.However,their inherently static geometry is an obstacle to many applications where dynamic tunability in their optical behaviour is required.Currently,there is a quest to enable dynamic tuning of metasurface properties,particularly with fast tuning rate,large modulation by small electrical signals,solid state and programmable across multiple pixels.Here,we demonstrate electrically tunable metasurfaces driven by thermo-optic effect and flash-heating in silicon.We show a 9-fold change in transmission by<5 V biasing voltage and the modulation rise-time of<625µs.Our device consists of a silicon hole array metasurface encapsulated by transparent conducting oxide as a localised heater.It allows for video frame rate optical switching over multiple pixels that can be electrically programmed.Some of the advantages of the proposed tuning method compared with other methods are the possibility to apply it for modulation in the visible and near-infrared region,large modulation depth,working at transmission regime,exhibiting low optical loss,low input voltage requirement,and operating with higher than video-rate switching speed.The device is furthermore compatible with modern electronic display technologies and could be ideal for personal electronic devices such as flat displays,virtual reality holography and light detection and ranging,where fast,solid-state and transparent optical switches are required.
